JPS646650B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing polyurethane,
It particularly relates to a method for producing polyurethane that has a high heat distortion temperature and excellent friction and abrasion resistance. Rigid polyurethane is broadly classified into non-foamed molded products and foamed molded products, and non-foamed molded products and low-foamed molded products are used as engineering resins in various equipment parts, automobile parts, etc. Conventional rigid polyurethanes are mixtures of one or more polyfunctional aliphatic or aromatic polyol monomers, polyoxyalkylene polyols, especially polyoxypropylene polyols, or polyfunctional aliphatic or aromatic polyester polyols. and a polyisocyanate component consisting of one or more aliphatic or aromatic polyisocyanates or polyisothiocyanates are cured and molded in the presence of a catalyst, a blowing agent, etc. However, these polyurethane molded products generally have poor heat resistance, and when heat distortion temperature (measured according to ASTM D-648) is used as a measure to evaluate heat resistance, conventional polyurethane molded products have a heat distortion temperature of 70 to 100 at most. ℃ was the limit, and it was difficult to exceed 100℃ with practical strength. On the other hand, heat resistance can be improved by introducing isocyanurate groups obtained by trimerization of isocyanate, but at the same time, the resulting molded product becomes extremely brittle and cannot be put into practical use. Generally, molybdenum disulfide and graphite are used to improve friction and wear resistance, but these compounds have no significant effect on hard polyurethane, but rather improve heat distortion temperature, tensile strength, and bending strength. and reduce impact resistance. In order to improve friction and abrasion resistance, we tried adding various silicone resins, fluorine oligomers, titanium coupling agents, silane coupling agents, encapsulated oil, etc., but none of them had foam-containing, impact resistance, It was found that properties such as tensile strength and bending strength deteriorated. Furthermore, fiber reinforcement had only a negative effect. The object of the present invention is to have high thermal stability and
Our objective is to provide polyurethane with excellent friction and abrasion resistance, and in particular, to provide a new polyurethane that has a high heat distortion temperature of at least 100°C, which could not be achieved with conventional hard polyurethane, and has practical strength, especially impact resistance. Our goal is to provide polyurethane that is of the highest quality. Another object of the present invention is to provide a heat-resistant, friction-resistant, and abrasion-resistant polyurethane that can be used at low speeds and high loads, high speeds and low loads, and high speeds and high loads. The present invention is a mixture consisting of 70 to 97 parts by weight of an aromatic amine-based polyoxyalkylene polyol with a hydroxyl value of 200 to 700 and 3 to 30 parts by weight of a polymer polyol obtained by graft polymerizing a monomer having a vinyl group to a polyether polyol. A heat-resistant, friction-resistant, and abrasion-resistant polyurethane with a heat distortion temperature of 100°C or higher, characterized by reacting a polyol component containing a polyol and having at least a difunctional hydroxyl group with an at least difunctional polyisocyanate component. Relating to the manufacturing method. The above polyurethane has excellent heat resistance, friction resistance, and abrasion resistance, but in order to further improve impact resistance, bending strength, and elongation, the above polyol component is an aromatic amine-based polyoxyalkylene polyol 50 with a hydroxyl value of 200 to 700. ~95 parts by weight and hydroxyl value 50~
Preferably, a mixed polyol consisting of 5 to 50 parts by weight of 1830 polyol is used. The number of functional groups, molecular weight, hydroxyl value, blending amount, etc. of the polyol having a hydroxyl value of 50 to 1830 are preferably determined depending on the required properties. For example, it is best to use diols to improve bending strength and impact strength.
To increase heat resistance and flexural modulus, use sucrose-based,
It is preferable to use a sucrose polyol. Furthermore, for the purpose of reducing the coefficient of friction in addition to improving bending strength and elongation, 70 to 97 parts by weight of an aromatic amine-based polyoxyalkylene polyol with a hydroxyl value of 200 to 700 and 3 to 30 parts by weight of a polymer polyol are added as the polyol components. Preference is given to using mixed polyols consisting of 1. On the other hand, in order to further improve heat resistance, a mixed polyol 100 of the above aromatic amine-based polyoxyalkylene polyol and polymer polyol is used.
Preferably, 5 to 30 parts by weight of a polyol having a hydroxyl value of 50 to 1830 is further added to the weight part. The polyurethane of the present invention can be used in various fields, and is particularly useful as various industrial parts that require heat resistance, friction resistance, and wear resistance, such as sliding material parts and other coatings. The above-mentioned at least bifunctional hydroxyl value 200~
Aromatic amine-based polyoxyalkylene polyols having a molecular weight of 700, preferably 300 to 500, can be prepared using known methods such as aromatic monoamines such as aniline or 2,4
- and 2,6-tolylene diamine (TDA) and so-called crude TDA, 4,4'-diaminodiphenylmethane and polymethylene polyphenylene polyamines obtained by condensation of aniline and formalin, ortho- or meta- or para-phenylene diamines. , a free primary compound obtained by adding one or more alkylene oxides such as propylene oxide and ethylene oxide to one or more aromatic diamines and aromatic polyamines such as meta- or para-xylylene diamine. Or it is a polyol in which substantially no secondary amine remains. In order to lower the viscosity and improve the processability of the above-mentioned aromatic amine-based polyol, in addition to the aromatic amines, the following aliphatic glycols and the like can be used as co-initiators in the synthesis stage. For example, ethylene glycol, diethylene glycol,
Examples include polyfunctional aliphatic glycols such as propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, glucose, sorbitol, and sucrose, aliphatic amines and aliphatic alkanolamines such as ethanolamine, diethanolamine, triethanolamine, and ethylenediamine. These co-initiators are preferably used in an equimolar or less amount relative to the aromatic amine. Specific examples of polyols having a hydroxyl value of 50 to 1830 include the following polyols. (a) An aromatic polyol having a hydroxyl value of 50 to 850 and having at least difunctional hydroxyl groups. (a) Hydroquinone, pyrogallol, 4,4'-
Polyol with a hydroxyl value of 250 to 600 obtained by adding an alkylene oxide such as propylene oxide or ethylene oxide to a monocyclic or polycyclic aromatic compound having at least two hydroxyl groups such as isopropylidene diphenol (b) Phthalic acid, isophthalic acid acid, terephthalic acid,
Polyols with a hydroxyl value of 300 to 500 obtained by adding any alkylene oxide such as propylene oxide or ethylene oxide to an aromatic polybasic acid such as trimellitic acid (c) Meta-xylylene glycol, para-xylylene glycol (d) Phthalic acid, isophthalic acid Acid, aromatic dicarboxylic acid such as terephthalic acid, its anhydride or its lower alcohol ester, and/or aliphatic dicarboxylic acid such as adipic acid, succinic acid, etc. as the acid component, and ethylene glycol, 1,4-butylene glycol. , aliphatic polyols such as trimethylolpropane, 1,4-cyclohexanediol, 1,
4-Cyclohexane dimethanol, β, β,
β',β'-tetramethyl-2,4,8,10-tetraoxaspiro(5,5)-undecane-
Polyester polyol with a hydroxyl value of 50 to 450, whose polyol component is an alicyclic polyol such as 3,9-diethanol or the polyol of (a), (b), or (c) above (b) Polyfunctional polyester polyol with a hydroxyl value of 800 to 1830 Aliphatic glycols. For example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, triethanolamine, etc. (c) A polyfunctional aliphatic polyol with a hydroxyl value of 300 to 800. For example, sucrose, sorbitol, glucose, pentaerythritol, trimethylolpropane, glycerin, ethylenediamine,
A polyol in which one or more alkylene oxides such as propylene oxide and ethylene oxide are added to one or more of diethanolamine and water. The polyols listed above are particularly preferred, and polyols other than these having a hydroxyl value of 50 to 1830 can be used. In the present invention, the polymer polyol is a polyether polyol graft-polymerized with a monomer having a vinyl group, and preferably has a hydroxyl value in the range of about 56 to 200. Specific examples of typical commercially available products include POP31/28, 32/30, 34/45, 36/28, and 40/45 manufactured by Mitsui Nisso. It has also been found that in the present invention, not only high HDT and impact strength can be obtained, but also workability, moldability, etc. can be effectively improved. The improved processability mentioned here means that by introducing the aromatic amine-based polyol, the viscosity of the aromatic amine-based polyol alone as well as the mixed polyol liquid is reduced.
It also improves so-called compatibility, where the polyol liquid and polyisocyanate liquid mix well even at room temperature.
Further, since the chemical reaction proceeds due to the moderate autocatalytic action of the aromatic tertiary amine, no catalyst is intentionally required. Therefore, since there is no need to add a catalyst to the polyol liquid, the storage stability of the polyol liquid is excellent. Furthermore, improvement in moldability includes increasing the strength of the polyurethane molded product upon demolding due to the introduction of a primary network using at least a bifunctional aromatic amine-based polyol. These polyols have a moisture content of 0.05% or less, preferably
It is necessary to keep it below 0.02%. Also, the polyisocyanates should be sufficiently degassed in advance. If these are neglected, unnecessary foaming will occur during the curing reaction. However, this is of course not the case when obtaining a foam. The polyisocyanate component of the present invention includes at least two types of polyisocyanate components in the field of polyurethane production.
Known functional aliphatic, cycloaliphatic and aromatic polyisocyanates can be used, among which aromatic polyisocyanates are particularly preferred. For example, 4,4'-diphenylmethane diisocyanate (MDI) and carbodiimide-modified MDI (e.g. Nippon Polyurethane Co., Ltd. MTL), polymethylene polyphenyl isocyanate (PAPI), polymeric polyisocyanate (e.g. Sumitomo Bayer Urethane)
44V), 2,4- and 2,6-tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), and the like are preferably used. The polyol component and polyisocyanate component are
The reaction can be carried out either by a one-shot method or a prepolymer method. The reaction between polyol and polyisocyanate preferably has an isocyanate index of 100 to 180, particularly preferably 105 to 180.
It is appropriate to carry out the test within the range of 160; outside this range, heat resistance decreases regardless of whether the isocyanate index becomes smaller or larger. Although the cause of this is not clear, it is presumed that it is due to a decrease in the substantial molecular weight of the polymer. In order to lower the coefficient of friction, the isocyanate index is preferably 100 to 115. However, since the reactivity decreases when polymer polyols and diols are added, it is preferable to slightly increase the isocyanate index. Furthermore, in order to further improve the friction coefficient and abrasion properties, it is better to add lubricating oil. Although a catalyst is not particularly required for producing the polyurethane of the present invention, known catalysts such as tertiary amines such as triethylene diamine and organometallic compounds such as dibutyltin dilaurate can also be used. However, isocyanate trimerization catalysts that produce isocyanurate rings are not preferred. Incidentally, it is also possible to obtain an inorganic filler-containing polyurethane by mixing the inorganic filler with the polyol or polyisocyanate in advance. Inorganic fillers include graphite, silicon carbide, aluminum oxide, molybdenum disulfide, etc.
It is effective in improving hardness, mold shrinkage, friction coefficient, wear resistance, etc. In addition, in the present invention, water, halogenated hydrocarbons such as trifluorotrichloroethane,
It is also possible to form a foam by using an organic blowing agent such as azobisisobutyronitrile. In the present invention, the curing reaction can be carried out, for example, as follows. First, adjust the liquid temperature of the compound from room temperature to 120℃.
Then, the temperature of the mold to be cast is set to 50 to 120℃,
Harden and demold. The cured molded product of the present invention is higher than the conventional polyurethane molded product as it is.
Although it has HDT, properties such as impact strength can be improved by further performing heat treatment at a temperature of 140 to 180°C. The heat treatment can be performed in an inert gas atmosphere such as air or nitrogen. The present invention will be explained below with reference to Examples. Reference Examples 1 to 5 OH value obtained by addition reaction of 5.6 mol of propylene oxide and 2.6 mol of ethylene oxide to 1 mol of 2,4-tolylene diamine (TDA)
400 TDA-based polyol (Takeda Pharmaceutical Co., Ltd. "GR-30") 900 g, molecular weight 200 diol [Sanyo Chemical Co., Ltd., "Sannix PP-200", OH value 560]
100 g of hexafunctional sucrose polyol [manufactured by Mitsui Nisso, "HS-700A", OH value 460] were each heated separately to 100° C. and dehydrated in vacuum. In addition, carbodiimide-modified MDI (Japan Polyurethane Co., Ltd., "Millionate MTL"), NCO content 28.8
%) 1000g was heated to 80°C and dehydrated under reduced pressure. Then, based on the formulation in Table 1, these polyol components were added to a beaker, and then MTL was also added as shown in Table 1, stirred in the beaker for 40 seconds with a propeller type stirrer, and then placed in a vacuum desiccator for 1 minute. The bubbles were defoamed. This mixed solution was immediately poured into a prefabricated glass mold with inner dimensions of 130 mm x 130 mm x 6 mm heated to 90°C, and placed in an air constant temperature bath at 100°C.
After reacting for 30 minutes, the cured product was taken out from the mold.
During this time, no bubbles were observed. then 160
Heat treatment was performed for 2 hours in an air constant temperature bath at 0.degree. C. to obtain a non-foamed, tough, rigid polyurethane. The heat distortion temperature of the obtained polyurethane is determined by ASTM,
D68 was used to measure the flexural modulus under a load of 18.6 kg/cm ² using ASTM, D790 was used to measure the Izot impact value using ASTM, D256 was used under notched conditions, and the friction coefficient was measured using a Toyo Baldwin friction tester. , dry condition, 20 m/min, and 5 to 60 Kg/ ^cm2 . Examples 1 to 4 Polymer polyol [manufactured by Mitsui Nisso, “POP40/
45'', OH value 110] was heated to 100°C and dehydrated in vacuum. Rigid polyurethanes were obtained in the same manner as in Reference Examples 1 to 5 based on the formulations shown in Table 2. Nao GR-
30, MTL and HS-700A Reference Examples 1 to 5 were used.

【table】

【table】

【table】

Claims (1)

[Claims] 1 A mixed polyol consisting of 70 to 97 parts by weight of an aromatic amine-based polyoxyalkylene polyol with a hydroxyl value of 200 to 700 and 3 to 30 parts by weight of a polymer polyol obtained by graft polymerizing a monomer having a vinyl group to a polyether polyol. Production of a heat-resistant, friction-resistant, and abrasion-resistant polyurethane with a heat distortion temperature of 100°C or higher, characterized by reacting a polyol component having at least a difunctional hydroxyl group with an at least difunctional polyisocyanate component. Law.